23 And when they came to Marah, they could not drink the water there because it was bitter. (That is why it was named Marah.)
Exodus 15:23 Cross References - MSB
Numbers 33:8
8 They set out from Pi-hahiroth and crossed through the sea, into the wilderness, and they journeyed three days into the Wilderness of Etham and camped at Marah.
Ruth 1:20
20 “Do not call me Naomi,” she replied. “Call me Mara, because the Almighty has dealt quite bitterly with me.